512TR wiring harness question

Is the odometer still working?

 

Between the 2 fuel tanks, through and down the fire wall and under the console to either the footwell, instrument panel or the fuse box. I have taken them out. Its a lot of work.

I would double check the color change. Most failures happen at connectors and none of the connectors is buried. The one under the coolant tank is a constant source of problems.


Sorry, that routing is for TR. Not sure if its same for 512. I know all engine management cables go through the firewall just in front of AC compressor but doubt if that applies for other cables.

TR512 harnesses were made by a then new contractor and were not as high quality. They suffered many inline failures so problems were not mostly confined to the connectors. I have repaired many mid harness failures. The so called "Cable multipliers" just a big crimp connector creating a branch for more component connections and those are very problematic and can be located anywhere.

 

Look around the back left side of engine compartment.. over and behind wheel

 

check if you have 12 V + at the instrument. both meters get different signals. so I think it is a problem of then 12 V +

what wire?

 

If the dead wire in question happens to go through a "cable multiplier" that could be an issue. When the harness was manufactured the crimp connector called cable multiplier were often over crimped partially fracturing the wire. Over time it can break completely. Bad news is you never know where they are. The diagram "may" give you a general idea.

 

@rumen1

Here's the wiring diagram:

https://www.dropbox.com/t/5aSxQnjR5VW3YRGW

I would confirm which wire is faulty first. Check for 5 volts at the sensor with the ignition on. I don't see a wire colour change in the diagram (maybe on the short section at the sensor?)

Break the circuit into sections and do continuity checks. Apart from the main connector 41042, possibly under the dash, there should be an engine accessories connector under the left hand bank intake ducting (41019).

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Apart from the odometer, are you getting any check engine lights on the dash? The speedo sends vehicle speed data to the RH Engine ECU.

Are you thinking of the Testarossa, Joe? I believe the speedo/odometer are on the same instrument on the TR.

 

sure they are, but both need continuous 12 V. and those not coming from the sensors

not have the wring diagram in mind, but normaly the meters get 12 V plus and from the sensors impuls with minus. may be it is vice versa?

 

Not sure what you mean, Joe.

I thought you might be talking about the earlier cars which had the odometer in a different spot. From what I can see, the instrument gets 12 volts on the green/white wire.

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The instrument then seems to send power to sensor and the sensor sends back the speed to the instrument. The signal goes to the gauge, but if I recall correctly, the instrument processes the signal and then sends it to the odometer and to the engine ECU.

12v power failure or sender failure can cause both speedo and odo to fail.

 

that is why I have written check if you have 12 V plus at the instruments

 

Thanks for the update. Please let us know if your tech finds the issue.

 

A squirrel is just a rat with better PR.

 

I believe euro 512yr did not come with bulbs in the check engine slots. Only US cars! The euro cars are missing the self diagnosis buttons next to the motronic 2.7 ecu’s.


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same on the Australian delivered as well.
I just put bulbs in them, works a treat..

 

Swiss cars differ from euro cars in some aspects.

 

My car was Italian delivery

 

His car is Swiss.

Not sure what the diffs are.

 

At minimum

https://www.ferrariparts.co.uk/Diagram/Ferrari/512-TR/011-Air-Injection-Ignition

 

looking at the diagram, you need part 50 and 51 to enable the check engine lights. Then you have to put bulbs in the instrument panel.